The overall objective of this project concerns the conversion of a relatively unexplored class of nucleosides- the aminonucleosides - into useful chemotherapeutic agents. Synthetic aminonucleoside analogs will be used to study metabolic activation and inactivation as a basis for a more rational design of metabolic inhibitors. The compounds prepared in this project will exhibit antitumor activity by inhibiting de novo nucleic acid snythesis by blocking the formation of nucleotide precursors.